Subject: RE: SNMPv3 Diffie-Helman key mib

From: Yost William <[email-masked]>
Date: Thu, 29 Jul 1999 22:53:46 -0500

Then you have to worry about key localization.  I believe any MIB browser or
SNMP manager who accepts a password will first convert the password to a key
and then localize the key to the agent, using it's snmp engine ID, the
procedure in the description of usmDHKickstartMgrPublic should specify to
localize the key to the agent's own engine ID after converting the password
to a key.

-----Original Message-----
From: Yost William 
Sent: Thursday, July 29, 1999 10:45 PM
To: [email-masked]'
Subject: RE: SNMPv3 Diffie-Helman key mib

The description of usmDHKickstartMgrPublic describes how to convert the
shared secret into the underlying keys.  I believe it is better to first
convert the shared secret into a readable 16 character password and then use
the password to key algorighm in RFC2274.  This is because a lot of MIB
browsers and maybe SNMP managers do not allow manual entry of keys, only
passwords you can type in by the keyboard.  The internally they use the
password to key algorithm to make a key.

-----Original Message-----
From: Mike StJohns [mailto:[email-masked]]
Sent: Thursday, July 29, 1999 4:12 PM
To: [email-masked]
Subject: SNMPv3 Diffie-Helman key mib

I've attached the most recent spin of the document I discussed at the IETF
in 
Oslo.  This will be going out as an internet-draft as soon as I get a 
permanent OID number from the IANA for the root of the MIB. My plan is to
have 
this published as an experimental RFC unless and until I can get the SNMP v3

community to take it or something like it up and adopt it.

Mike

---

From: "Mike StJohns" <[email-masked]>
Date: Fri, 30 Jul 1999 10:50:01 -0700

> localize the key to the agent's own engine ID after converting the password

Due to the nature of DH, the key is already localized.  Consider:

Manager M

Device A
Device B

The shared secret used between M and A is DH (M, a) or DH (m, A) where M is the managers public number, m is the managers private number, A is A's public number, a is A's private number and DH () is the diffie-helman key agreement function.

The shared secret used between M and B is DH (M, b).  

And so on for the rest of the other devices.  Each individual agent generates its *own* random number and derives its public number from that random number.  The shared secret between the agent and the manager would only be identical with the shared secret between another agent and the manager if the two agent's random numbers were identical.

Mike